Vista considerations

From ISXKB

Windows Vista now includes a far stricter LUA system. This pretty much stops all applications making system wide changes without asking the user.

Inno 5.1.9 and later handles this fully for the install, and asks for elevated permissions so it can write anything it needs.

Due to this permission elevation, anything run from the install will also run with full access to the system. Whether your application is "Vista compatible" or not, this is a very bad idea.
Unfortunately, Microsoft "forgot" to add the ability for en elevated application to drop them when running anything else so the only way around this is to add the OnlyBelowVersion: 0,6 on the [Run] entry to so the option is not available on vista.